Let-off and tension mechanism for looms



Dec. 27, 1927. 1,654,126

l G. F. HuTcHlNs LET-DFF AND TENSION MECHANISM FOR LOOMS Filed Oct. 1'7 1925 Geafge lie/)7s mmh f7 Patented Dec. 27, 1927.

f UNITED STATES insane' PATENT oFFicE.

GEORGE F. HUTCHINS, OF WORCESTER, MASSACHUSETTS, ASSIGNOR TO CROMPTON AND KNOWLES LOOM WORKS, OF WORCESTER, MASSACHUSETTS, A CORPORATION 0F MASSACHUSETTS.

LET-OFF AND TENSION MECHANISM FOR LOOMS.

Application filed October 17, 1925. Serial No. 63,177.

This invention relates particularly to looms for Weaving heavy fabrics.y In certain types of looms used for this purpose, and particularly in heavy 'duck looms, it is very desirable that the tension on the Warp threads be held as nearly uniform as possible, particularly after a pick-out has occurred.

It is the object of my invention to accomplish this result by providing a regularly operated friction let-off mechanism to produce tension on the Warp threads during the normal operation of the loom, in combination with an auxiliary tension device for producing Warp tension at certain desired times. This auxiliary tension device is commonly used only after a pick-out and is normally inactive.

In the preferred form, this auxiliary tension device is rendered operative manually after the occurrence of a pick-out and is locked out of operation when the .normal weaving condition of the loom is restored.

My invention further relates to arrangements and combinations of parts which Will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings in which Fig. 1 is a partial side elevation of a loom embodying my improvements,

Fig. 2 is a view similar to Fig. 1, but showing the parts in a different position, and

Fig. 3 is a sectional plan view of the mechanism shown in Fig. 1.

Referring to the drawings, l have shown a portion of a loom frame 10, a lay 11, lease rods 12 and guide rolls 13 and 14, all of the usual construction. The warp threads W are indicated as being drawn from a creel (not shown) and pass over a guide roll 15 to a friction drum 16. As they leave the drum, the Warp threads pass under a guide roll 17 and are then led to the guide rolls 13 and 14 previously described. The guide rolls 15 and 17 are so positioned that the Warp threads engage substantially three-quarters of the surface of the friction drum 16.

The drum 16 is provided with a friction head or pulley 2O at one or both ends thereof and each such head or pulley is engaged by a friction band 21 connected by an adjustable link 22 to an arm 23. The arms 23 are fixed to a cross shaft 24 pivoted in the loom frame 10, and one of the arms is connected by an adjustable link 25 to a hand lever '26 pivoted at 27 on the loom frame.

The front end of the hand lever 26 rests upon a support 28 which may be'vertically adjusted by a screw 29 and handle 30. The friction upon the drum 16 is thus convenientl ly adjusted from the front of the loomby merely turning the handle 30'in'a desired direction. p

The warp threads pass through the usual harnesses (not shown) and the WovenV fabric is drawn over the breast beam 31 by any usual take-up mechanism .also not shown. All of the parts thus far described are of the usual/construction and in themselves form no part of-my present invention, which rein bearings in a supporting frame 36 pivoted onv a cross shaft 37 on the loom frame. VVeig-hts 38 are mounted on the rearward ends of the frame 36 and tension may be adjusted by adding or removing weight elements as desired. The roll 35 is thus supviorted in a position between and below the guide rolls 13 and 14 and the Warp threads YV are caused to pass over the guide roll 13, under the tension roll 35, and over the guide roll 14.

A latch 40 for each side of the frame 36 is mounted upon a cross rock shaft 41 pivoted to the loom frame at the rearv portion thereof. 'and these latches are adapted to engage the rear ends of the frame 36 and to lock it in raised position. Adjustable links 42 connected as at 43 to the latches 40 are attached to brake levers 44 swinging about fixed pivots 45 and engaging the front surface ofthe friction drum 16.

The brake levers are connected by adjustable links 4S to arms 49 .secured to the cross shaft 37 as at 50. vOne of the arms 49 is also connected by an adjustable link 51 to a lever 52 secured to a stub shaft 53 rotatably mounted in the loom frame. A handle 54 is secured to the stub shaft and affords means for rocking the lever 52. Pivotally mounted on the loom frame is a latch 55 having a tooth 56 to enter notches 57 and 58 formed in the upper end of lever 52 by means of which the brake levers 44 may be locked in two different positions. The loom frame slacknessof the Warps as they pass aroundY the roll 35 at the time of a pick-out. The roll 62 may be held in raised position by means of notches 61 when accessto the Warp;`

is desired.

Having described the construction ofmy im roved let-off and tension mechanism, I W'il l n'oW describe the operation and method ofuse thereof. During the normal running of th'e loom the parts are in the position shown' in Fig. 1, with the frame 36 lcclied in raised position and with the bra-ke levers 441W'itlidr'avvn from the friction drum 1G.

llVheI'iA a defect occurs in the cloth such as requiresV a pick-out, the Weaver turns the take-up mechanism backward to loosen the Warp and a suflicient number of weft threads are picked out to remove the defect in the fabric. The Weaver then rewinds the takeupY mechanism sutliciently to restore the original' tension on the Warp, which may be determined by causing the friction drum to slip slightly', letting off an additional amount ofwarp'.

The Weaver then raises latch 55 to Withdraw tooth 56 from notch 57 and' moves the handle 54 rearwardly and lowers the latch to allow the tooth to enter notch 58. This action causes the latches 40 to be moved rear- Ward to the position shown in Fig. 2. and at the same time causes the brake levers 44 to engage the friction drum 16. The Weights 38 are previously adjusted so that the tension roll 35, when released, will apply a tension to thefvvarp substantially equal to that supplied' by the friction drum 16. y

After the roll 35 is thus released, the Weaver again turns the take-up mechanism reversely to let the fabric back until the fell ofthe cloth is brought to the proper positi'on for` renewed Weaving. The Warp thus reversed is immediately taken up by the tension roll 35, which moves downward as fast as permitted by the Warp as the latter is let back.

The Weaving is then resumed, the brakeY 16. The Weaving thereafter proceeds in the.

usual manner.

It Will thus be seen that I have provided means for producing uniform tension upon thel warp by tvvoA differentl tensionI devlces and that the auxiliary tension roll 35 is effective to take up the slack Warp arising from. a. pick-out' Without the necessity of Winding the friction drum 16 backward, a procedure Which has'serious objections when the Warps are drawn from a creel. It Will also4 bernoted that theA frame 36 is relatively heayy to insure a parallel motion of roll 35 and that roll 62 prevents the Warps from crossing each other near the roll35 when the cloth is let back. If` the brake levers 44 should be temporarily outl of order or for. any reason are inoperative to applyl extra tension on the normally operative drum, they usual hand controlled tension lever 26li may be raised from its supportingv block to apply the additional pressure needed when the. normally idle device becomes operative.

Having thus described my invention and. the advantages thereof,y I do not Wish tol be limited to the details herein disclosed other wisey than as set forth in the claimsfbut What I claim is:

1. In a loom, a regular friction Warp tension mechanism including a friction drum,r said mechanism providing for letting off the.

warp at substantially uniform Warp tension during normal Weaving, and a normally in.-

active auxiliary warp tension device effective, When placed 1n active. operation,y toy provide. substantially the same Warp tension after a.

pick-cnt, said friction drum being held in fixed angular position until thel auxiliary tension devicel is returned to normal inactive position.

2. In a loom, a regular friction warp tension mechanism including a friction drum. said mechanism providing for letting oli the Warp at substantially uniform Warp tension during normal weaving. and a normally inactive auxiliary warp tension device. eifective, when placed in active operation, to provide substantially the: same warp tension after a pick-out, said friction d-rumbeing held in txedi angular position until the auxiliary tension device is returned to normal inactive position, and said auxiliary tension device being gradually moved toward such normal inactive. position. by theA taking up.A of the Warp between the fell of the fabric and. said friction drum bythe weaving thereof?.

3. A mechanism as set forth in claim 2, in Which means is provided to lock said auxiliary tension device in inactive position.

4. A mechanism' as set forth in claiml 2, in which means is provided to lock said auxili ary tension device in inactive position: and' in which means is also provided to place. additional friction on said friction drum when said auxiliary device is rendered operative.

5. In a loom, a regular Warp tension mech anism including a friction drum engaged` by the warp and exerting normal tension lili) lug',

thereon during regular operation of the loom, means to hold said friction drum at times from rotation, a normally inactive auxiliary tension device engaged by the Warps between said drum and the tell of the fabric, said auxiliary device being effective to control the warp tension after a pick-out and while said friction drum is thus held trom rotation, and means to adjust the tension produced by said auxiliary tension device to correspond to the tension produced by said regular tension mechanism.

ti. ln a loom, a regular warp tension mechanism including a t'riction drum engaged by the Warp-s and exerting normal tension there on during' regular operation of the loom. a normally inactive weighted tension roll engaging" the Warp between said drum and the fell of the tabric, the weights on said roll beinel adjustable, and means to render said tension roll inactive during the regular operation otl the loom.

7. ln a loom, a regular warp tension mechanism including a Vfriction drum engaged by the warp, an auxiliary tension roll` means to lock said roll in raised inactive position, and brake levers connected for simultaneous operation with said locking means and ettective to ho'ld said drum trom rotation when said tension roll is released t'or operation.

8. The method ol' controlling warp tension during and after a pick-out which consists in lettingr back and loosening' the warp and pickin;r ont the necessary weft', takingr up the warp to substantially restore the original tension. unlocking an auxiliary tension device. renderingr the regular let-off and tension mechanism inactive, letting back the Warp to the weaving' point under the tension of said auxiliary device. Weaving additional fabric until said auxiliary tension device is moved by the taking' up ofthe Warp in weavingT to its normal inactive position, locking said auxiliary device in such inactive position,

restoring' the regular let-ottl and tension mechanism to active operation, and thereafter continuing to Weave fabric under the action of said regular let-off and tension mechanism.

9. In a loom having a warp supply, a pair ot' tension devices meh cti'ective when in use 'to automatically supply substantially the same normal tension on the Warp and each operative while the other is prevented from supplying4 Warp for Weaving and each capable ot bet'comingg,- operative, one of said devices being automatically movable to take up slack warp, and means to render said devices alternately operative to supply Warp under normal tension for the weaving operation.

lt). In a loom havingr a warp supply, a pair of tension devices each effective when in use to apply substantially the same normal tension to the arps, one of said devices tensioning the warp while said warp remains in its normal path of travel during Weaving and the othc" device tensioning said warp by Ffubstantal dlnlacement thereof from its normal path ol.l travel, and means to render either one of :aid devices etfective to supply tra rp under normal tension for weaving and to render the other device sinm'ltaneously inetl'ective tor supplying warp under normal tension for weaving.

l1. ln a loom having a warp supply, alternately operative devices effective to apply aulratantially the same uniform tension to the warp at tvfo .substantially separated points` in the path of travel of the warp, one of said devices tensioning the Warp while said warp remains in its normal path of travel during weaving, and the other device tensioning?r the warp by' substantial displacementi thereof from its normal path of travel.

In testimony whereof l have hereunto at'- fixed my signature.

GEORGE F. HUTCHINS. 

